Quantifying the psychological value of goal achievement.

It is often assumed that people put forth the least amount of effort necessary to obtain a reward. This assumption is consistent with so-called "rational" economic models of behavior. Yet these models rarely take into account the motivating effects of goals, which may lead to departures from objective reward maximizing behavior. We present an experiment in which people make a series of prioritization decisions whilst pursuing two approach or avoidance goals. Participants were rewarded $10 if they achieved both goals on a randomly selected trial, and either $0, $2.50, $5, $7.50, or $10 if they achieved only one. Bayesian parameter estimation was used to examine the subjective values that people placed on various goal achievement outcomes. The results suggested that people often discounted the achievement of the first goal, relative to a reward maximizing model, particularly when pursuing avoidance goals. These results were most evident among participants who could obtain the full reward after achieving just one goal, yet behaved as if achieving one goal was only half as valuable as achieving both. Our findings question the notion that people put forth the least amount of effort required to obtain a reward. They suggest that when tasks have explicit goals, people may even sacrifice financial reward to achieve the goals.